


Catalyst

by Anonymous



Category: Voltron: Legendary Defender
Genre: M/M, SHEITH - Freeform, Sex Toys, Shiro's galra arm, Strap-Ons, Trans Keith (Voltron), Trans Shiro (Voltron), Vibrating Hands, trans author
Language: English
Status: Completed
Published: 2018-06-29
Updated: 2018-06-29
Packaged: 2019-05-30 02:38:50
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,371
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15087179
Author URL: https://archiveofourown.org/
Summary: "You orderedthat?" Keith asked."Of course. For both of us."





	Catalyst

**Author's Note:**

  * For [kiishii](https://archiveofourown.org/users/kiishii/gifts).
  * In response to a prompt by [kiishii](https://archiveofourown.org/users/kiishii/pseuds/kiishii) in the [voltron_sheith_kink_meme](https://archiveofourown.org/collections/voltron_sheith_kink_meme) collection. 



> A short fic for an idea I had after reading this prompt on the Sheith kink meme. Someone on the trans-Sheith discord also requested strap-on sex, so I decided to roll the two together into one fic. I hope y'all enjoy this small offering.
> 
>  tw: some afab language
> 
> **Prompt (from Sheith kink meme):**
> 
> Shiro’s realizes that his prosthetic has a vibrate function with varying levels and pulses. He decides to experiment this new discovery with Keith.
> 
> Can be written in the main VLD universe or any AU. **Trans!Keith is strongly preferred.** Any use of other ropes, toys, or other sex acts can be written at author’s preference.

****The package was innocuous enough. Shiro promised Keith he’d treat him to something special after their latest trip to the nearest trading post. And as if hearing his wish, an out-of-the-way novelty sex shop had exactly what he needed in-stock: a firm, weighty replica of an alpha galra cock. Initially, Shiro felt turned off at the idea of using it on Keith, as he wasn’t quite sure what his reaction would be given Keith’s own fraught relationship to his bits. But on the other hand, he could pass it off as an ironic joke, and both of them could laugh at the ridiculousness of such a toy existing in the first place. Either way, Shiro quickly traded his funds for the toy and once the moment was right, he’d surprise Keith with his new discovery.

“That is…” Keith slowly scanned the wide, dark violet object with an expect skepticism. “Huge.”

“I thought you’d like it,” Shiro added. He adjusted the harness, running his finger under the leather straps as to ensure they weren’t too tight. Satisfied, he stroked the realistic vein underneath his synthetic cock, pleased to find that it bounced happily from the attention. Of course, that wasn’t all there was to the toy – it was double-sided. Before showing it to Keith, Shiro had painstakingly lubricated his cunt in the bathroom, pulling up his knees with an excitement he rarely got to experience nowadays. Dipping three of his fingers into his folds, Shiro sucked in his breath and slipped the pointed head of the cock back against his ring. Resisting at first, Shiro winced as he felt the middle of the cock stretch his cunt wider, pushing against his walls until finally bottoming out to where the strap-on began. With a sigh of relief, Shiro had finished applying his harness, full with the warm sensation of the cock’s tip rubbing against the innermost of his cunt. Had it been any larger, Shiro shuddered at the thought of it hitting his cervix and massaging that spot he rarely managed to reach.

Keith bit his lip, and unfolded his legs on their shared bed. A pair of shorts rode up his ass, tightening around the fleshy top of his thighs he shifted his weight. Shiro took this as his cue to come join him, running the flat of his palm up Keith’s side before stripping down the nylon of his waistband. Keith laughed, brushing his fingers through Shiro’s hair, completely fixated on the determined focus on the other man’s eyes.

“Take it easy,” Keith teased. “I’m ready whenever you are.”

“Mhm,” Shiro answered. “And I’ve been waiting weeks for this, you know that?”

And with that, Shiro slipped his hand down Keith’s navel, exploring until he found the soft trail of hair leading to Keith’s redden clit. Keith made a short gasp at the touch. Shiro smirked at the reaction, more than pleased to find that Keith was already substantially wet and ready for the length of galran toy staring him down.

“Are you sure this will be enough for you, baby?” Shiro asked. “It’s pretty big but, still. I know how you are.”

Keith felt his face burn with embarrassment. Sometimes he regretted sharing his fantasies with Shiro – this one in particular involving being taken prisoner by galran arms. Of all people to roleplay with, Keith would always choose Shiro. Not only did it feel the safest, but he trusted Shiro’s good judgement and ability to make things as comfortable and pleasurable as possible, no matter the scene. Keith swallowed and nodded, acknowledging that he was beginning to sweat from anticipation, knowing well that he was already soaked from the thought of Shiro’s cock stretching him wide open.

“I’m ready,” Keith said. Carefully, he pulled down the rest of his shorts and underwear, sliding them past his knees and make rid of them on the floor. Reaching for the drawer, Keith pulled out their private vial of lube, excitedly applying a generous amount on his fingers as Shiro grabbed the meat of his thigh. With a quiet laugh, Keith pried open his labia, using his lubricated hands to tease his folds open, prod at his twitching hole begging for attention.

“Wait. I have something else,” Shiro added. A soft, electric hum filled the room. Keith opened his mouth, not quite sure what to make of it until he lowered his eyes on Shiro’s hand. Suddenly it clicked – and he felt the knot in his stomach tighten straight away. Shiro aptly opened and closed his galra hand as it vibrated, appreciating the look of awe on Keith’s face at his recent discovery.

“I figured this means I don’t need to buy us a separate vibrator,” he explained. “You like it? It must have some practical purpose but for the life of me, I have no idea why you’d want to use it for anything else.”

Keith smirked. Shiro caught a flash of fire in his eyes, that excitement he was willing to tease out if it meant both of them could enjoy the night more. Throw it as far as they could.

Placing his regular hand over Keith’s, Shiro carefully placed the tip of his vibrating fingers over Keith’s clit, making sure to roll back the hood and massage the soft underside. Keith sighed and found himself easing back into their pillows, his shoulders loosening at the pulsation of Shiro’s vibration. The touch was unexpectedly warm – nothing felt synthetic about the way Shiro cupped Keith’s hardened clit and ran the pad of his thumb over its swollen tip.

“Ha, fuck,” Keith choked. “Fuck, Shiro.”

“Feeling good?”

“Yes, yes,” Keith begged. “I want you inside me. I want your hands and your cock. I wanna be wide-open.” Spreading his legs, Keith shifted his weight so that his knees were pulled up to his chest, the fat folds of his cunt fully exposed and begging for swollen cock. Keith felt that tight knot return to his chest as Shiro’s hand slipped through his folds again, the vibration stopping and starting as if to coax him further along their play session. A tight, electric sensation built itself up behind Keith’s clit, threatening to spill itself inside him unless he begged Shiro to stick his hand inside him. Fuck his walls from the inside out, loosen him up for the galran cock staring him in the face. Even if Shiro couldn’t give him his seed – Keith still felt as if it were the real thing: Shiro’s wet, full member ready to split him open and cool the burn raging inside him.

“You really like that, huh?” Shiro asked.

“Uh-huh,” Keith moaned. “Shiro, please.”

“Use your words. Hm? What do you want?”

“Your hands – I want you to fuck me with your hands.”

“Is that it?”

“N-no…I want your cock too.” Keith wasn’t ashamed to admit, yet he still felt his cunt twitch in anticipation, his hole ready and needy for the attention promised to it.

“That’s what I figured,” Shiro teased.

Bringing up two digits, he quickly slipped them inside Keith, scissoring him open before adding a third and sliding them past the knuckle. Keith moaned from his chest, losing his breath for only a second before he felt the root of his clit throb away. As he was about to move his hand over to rub himself out, Shiro stopped him and expertly moved his fingers from Keith’s dripping hole to his begging red clit.

“Oh no baby, I didn’t forget,” he said.

Keith closed his eyes. A deep, warm sensation built itself under his skin, raising goosebumps as Shiro’s vibrating fingers cupped his clit once more, now soaked in his own fluids. It felt impossibly good – he curled his toes, feeling the vibration travel from his cunt down his thigh, as if his entire body was in synch with the motions of Shiro’s vibrating hand. Keith gasped as Shiro rolled his clit, spreading his labia open again for good measure to tease where his hood and head met, softly planting the pads of his fingers in-between.

He made circles with the tip of his fingers, slowly bringing them from the edge of the clit’s head to the base, then quickening his pace without warning. Keith bit down on his lip, stifling a moan as the circles became more furious, massaging and kneading his clit with a break-neck focus.

“Oh fuck, oh fuck,” Keith cried. “Fuck. _Fuck_.”

“Like that, baby?”

Keith blinked tears from his eyes. He swore his entire cunt was twitching, his hole begging to be filled, his inner-thighs soaked at it wept to be stretched. Without realizing it, he felt the tip of Shiro’s cock rub against the rim, brushing through his folds as it made a soft, wet noise. Keith held his breath, inhaled through his nose as the tip of the cock muscled its way through his needy folds, brushing only lightly against his weeping clit as Shiro’s hand continued to bathe it in vibrations. The tip felt almost too right, too tight and comfortable as Keith felt himself practically suction Shiro in, feel the sculpted ridges of the cock bump and knead his velvet walls.

Keith widened his legs as Shiro bottomed out. Shiro began shuddering as the opposite end of the strap-on numbed his cunt, fucking itself deeper as he slammed back into the other man. A sloppy popping sound emitted as Shiro pulled out, his cock already soaked and glistening slick from Keith’s eager insides. Without pause he plowed back in, this time increasing his pace as he kept up with Keith’s clit, keeping the digits of his vibrating hand fully occupied. Keith threw his head to the side, completely engrossed in how effortlessly Shiro committed himself to double-duty. He was being utterly spoiled -- and that thought only made Keith’s cunt tighten more around the already wide base of Shiro’s aggressive cock. With a hefty moan, Keith rolled himself on his hip, using his arm as a balance as he raised his leg up to give Shiro more room. He needed this -- he needed the feeling of fire burning in his stomach again, needed it to return with aplomb if he was going to come. His only signal was a half whimper as Shiro formed a knuckle and brushed it up against his messy folds, pushing his stickied pubes aside to his sweet pink nub.

“You love it,” Shiro teased. “You love your cunt wrecked. Is that what you want? Ruined by a big galran dick?”

Keith burned up. He didn't want to admit it with words but swallowed his pride anyways and nodded out of desperation. Yes, of course he wanted to be plowed, wide and open to be bred and fucked like a toy. He wanted Shiro to give him everything he couldn’t have. For a moment, both could indulge in their innermost fantasies to satisfy their needs. The thought made Keith’s heart jump with anticipation, the excitement making his clit throb as Shiro’s cock rubbed against his hood. With his vibrating hand still on his navel, Shiro probed the entrance of Keith’s wet hole until he whimpered, watching as it accommodated the finely sculpted head of the cock.

“This is amazing,” Shiro gasped. The opposite end of the cock rocked against his cunt, kneading up into his walls and the tightened passage to his womb. He swallowed, feeling the prickle of sweat against his nape as Keith wiggled underneath him begging for more.

“Be patient, kitten,” he teased. “I’ll get you there. We’ll both get there.”

“Mm,” Keith whined. “Hurry up. This is punishing.”

Adjusting himself so he could prop his chin on his hand, Keith felt the rest of his body sink into the bedding as Shiro played his cunt like an instrument. As the head of the strap-on pushed deeper inside, Keith spread himself wider, lifting up his leg just enough so Shiro could comfortably bottom out. With ends of the cock deep inside them, Keith shuddered at the realization that Shiro was feeling the same sensations as him – that they were sharing this intimacy with eachother unfiltered.

“Fuck, I’m glad we did this,” Keith panted. “This is nuts. I love it.”

“Me too. You’re so tight. It’s wild. I can _feel_ how tight you are, Keith.”

Keith laughed. A low hum filled the room. Carefully, Shiro rubbed the sides of Keith’s erect clit with two fingers, nesting it between the vibrating digits. As if on command, Keith gasped and curled his toes, another bolt of pleasure slipping through his cunt and into his hot belly. It was almost becoming unbearable – the rate at Shiro touched him with his galran hand and fucked him with the strap-on was something neither of them could’ve anticipated. It was a brave new world. Without hesitation, Keith pulled his knees back further, raising his crotch and exposing the swollen lips of his cunt to Shiro without shame.

“Hurry up,” Keith begged. “I’m gonna start sounding pathetic otherwise.”

“Of course,” Shiro answered. “Anything for a good boy.”

Finally the hum of Shiro’s hand matched Keith’s purring, one hand cupping his thigh and the other fluttering the head of his clit. Keith sucked in his breath as Shiro pulled out and slammed back into his hole, both of them feeling the same force in which the cock pried deeper inside. Buried in Shiro’s walls, the other man moaned, felt himself clench into the cock’s explorary length as Keith hurriedly rocked himself back against his touch. Gravity seemed to work in their favor, and Shiro quickly used his unoccupied hand to pull Keith closer, tighten his grip on the boy and tease out another exhausted moan as he flicked the bottom of his clit. With another cry, Keith felt his entire body tighten, goosebumps rising as Shiro pounded back into it, widening and widening his hole with each re-entry.

“You know how to use that thing,” Keith laughed. He couldn’t help it. Shiro was enjoying himself way too much. It was almost silly that they hadn’t tried this earlier.

“Well, you know, practice makes perfect.”

“That’s rich coming from you.”

“Uh-huh,” Shiro mocked. “Let’s see who bottoms next time, then.”

It was going to be a good night.

**Author's Note:**

> [check out my archive](https://archiveofourown.org/users/newtype)


End file.
